Water soluble brightener composition



U 'of the coumarin compounds.

. further dilution of thesolution, thus interfering with I WATER SOLUBLE BRIGHTENER'COMPOSITION No Drawing. Application May 6, 1955 Y seminal. 506,664

10 Claims. (Cl. 252-3012) This invention relates to optical bleaching agent compositions and to a process for the preparation thereof. More part cularly it relates to optical bleaching agent compositions comprising an inorganic-salt of av coumarin type bleaching agent and an organic acid of the group consisting. of maleic, fumaric, oxalic, tartaric and benzene phosphonicacids.

Compounds ofthe'7 -amino coumarin type are known for their optical bleaching agentproperties, producing a whitening or brightening effect on various fabrics by the emission of blue fluorescence to compensate for the natural yellowing of the cloth. The compositions includ- United States Patent ing'jbrightenersof the coumarin type, described above,

are especially useful on certain types offibe'rs and fabrics for-this purpose. .,One important. application of these is me. step in the processing of fabrics such as wool, acetate, nylon, .etc., whereby-a, brighter, whiter appear- "anceis ,imparted to thecloth, In such applications the I 1 bleacing agent is applied'to the fabric from an acidic aqueous'bath. The optical-bleaching agents as prepared, are, however, not' water 'soluble'and it'is therefore necessary for the operator first to dissolve the agent in an furic acid and then add this solution to the bath in preparation for-the processftre'atment. ,Ifthe aqueous Y solubility of the'agent could be improved,'this pre-solution step could be avoided. Various attempts have been made to produce easily water .solublec'oumarin' brightening agents by insertion. of

various solubilizing groups' In the coumarin molecule,

however, this does not produce satisfactory results since T the products generally showinferior optical bleaching properties. The coumarin compounds containing amino groups form salts with strong inorganic acids soluble in W'ate'r,=but these are'not suitable since there is a'strong tendency to hydrolysis in the bath with the precipitation This is especially true on 'the bleaching effect.

Someof the coumarin brighteners have been mixed 1 with various solid inorganic compounds to make water Such mixtures have been found soluble compositions.

Even when deliquescence 1s to be quite hygroscopic.

. not observed, there is caking from absorption of water a coumarin type of bleaching agent with certain organic acids show good water solubility, avoiding hydrolysis and" precipitation of the coumarin compound upon furtherdilution of the bath in which they are used. Furthermore, the compositions are resistant to absorption orv takingup of moisture from the atmosphere to the extent that the tendency for caking and formation of wet I sticky products upon atmospheric exposure is greatly 1 Y diminished in many cases.

' organic solvent orina strong mineral acid such as .sul-

2,844,539 Patented July 22, 1958 I C2115 I l where X is an alkyl group such as methyl-or ethyl and Y is hydrogen, alkyl or alkenyl, and where X and-Y may be joined to form a polymethylene chain. As examples of the coumarins suitable may be mentioned 4-methyl-7- diethylaminocoumarin, 3-allyl-4 methyl-7-diethylaminocoumarin, 3,4-tetramethylene 7 diethylaminocournarin,

Y and the like. A particularly preferred species, however, is 4-methyl-7-diethylaminocoumarin. These are used in the form of a strong inorganic acid salt such as the sulfate, chloride, phosphate, nitrate, etc. We particularly prefer,' however, to use the sulfate because of its ease of preparation. x I

The acids which can be satisfactorily used in our invention are a group of relatively cheap available organic acids, namely,voxalic, maleic, fumaric, tartaric, and benzene phosphonic'acids. The choice of these acids over the many other possibilities among acid compounds is not governed by acidity. .-Other acids of about 'thesame acidity (e. g. malonic or citric) are not usable because their mixtures with the coumarin brightener salts cake up as do the'mixtures with acidic inorganic-compounds. Consequently, our-invention is limited to'the use of these specific acids. a i I Various proportions of the acidicingredient may be used in our compositions from about 2.5 to about .15 parts with one part of the coumarin salt (calculated as the base). However, we prefer to use. from about 3.5 to9parts, Y 1 6 Inpreparing the bleaching agent compositions of our invention the coumarin derivative is first converted to Y .the inorganic acid salt. 'This is accomplished by dissolving the coumarin derivative in 'an aqueous solution of the inorganic acid of .suflicient concentration to cause easy solution. Theinorganic acid salt is then isolated by ordinary methods, such as salting out by addition of the ,sodium -salt of. thecorresponding, acid. The coumarin salt is then admixed with the acid ingredient by ordinary mixing, grinding the two together,.treatment in a ball mill,'-'or similar operations. A 'dry powdery product is thus obtained.

The optical bleaching compositions are useful for brightening fabrics of protein fibers such as'wool and silk, superpolyamide fibers such as Nylon, acetate rayons, etc. Theylmay be added directly to the bath for fabric treatment from a concentrated aqueous stock solution Y without resulting in precipitation of the coumarin compound. In addition, the compositions may be used in other applications where the coumarin type of bleaching agent eflfect is desired.

The presence of the organic acid results in a product which is easily soluble in water and leaves no oily film. Furthermore, no precipitation takes place on extreme dilution of the bath. The acid ingredient evidently has a solubilizingeffect and helps maintain the coumarin compound in solution. Y

The invention may be illustrated by the following ex-' amples in which parts are by weight unless otherwise specified.

Example I To 1000 parts of 20% by weight aqueous sulfuric acid at 60 C. is added 70 parts of 4-methyl-7-diethylaminocoumarin with stirring. To the solution which forms there is added 300 parts of anhydrous sodium sulfate. The stirring is continued without the application of heat until the mixture reachesroom temperature. *Theso'lid sulfate salt of the coumar in"-derivative is then removed by filtration and dried.

155 parts of sulfate (98.4 parts of coumarin base) is then blended with 845 parts of tartaric acid by grinding the acid with the sulfate salt. The resulting powder maintains a dry appearance when exposed to a humid atmosphere and dissolves readily in water leaving no oily film on the surface or any insoluble matter. It does not cake on standing. The blend contains 8.6 parts of the acid per part of the coumarin brightener, calculated as the base.

Example 2 The procedure. of Example 1 is followed except that 358 parts of oxalic acid are used in ,place of the tartaric acid. The resulting powdery product maintains a dry appearance and a powdery form when exposed to a humid atmosphere and dissolves easily in water leaving neither oily film on the surface nor any insoluble matter. It does not cake on standing. The blend contains 3.6 parts of the acid per part of brightener, calculated as the free base.

Example 3 The procedure of Example 1 is followed except that benzene-phosphonic acid (C H --PO(OH) is used in place of tartaric acid. The resulting powder composition dissolves readily in water.

Example 4 The sulfate salt is prepared as in Example 1. The sulfate is then blended with 1270 parts of tartaric acid. The resulting mixture dissolves easily in Water. The blend contains about 13 parts of acid .per part of coumarin base.

Example 5 The procedure of Example 1 is followed except that maleic acid is used in place of tartaric acid. The resultant mixture dissolves readily and completely in water. It does not cake on standing even in high humidity.

Example The procedure of Example 1 is followed except that 3- allyl-4-methyl-7-diethylaminocoumarin is used 'in place of the 4-methyl-7-diethylaminocoumarin. The' product is readily soluble in water and does not cake on standing.

Example 7 The procedure of Example 1 is followed except that 4 3,4-tetramethylene-7-diethylaminocournarin is used in place of 4-methyl-7-diethylaminocoumarin, with similar effectiveness.

Example 8 The procedure of Example 1 is followed except that 3,4-trimethylene-l-diethylaminocoumarin is used in place of 4-methyl-7-diethylaminocoumarin. A similar product is obtained.

We claim:

1. A solid optical bleaching composition comprising a mixture of 1 part, calculated on the free base, of a strong inorganic acid salt of an optical bleaching agent of the formula:

wherein R and R are selected from the group consisting of hydrogen, lower alkyl, lower alkeny1, and a jointly formed trim'ethylene bridge, with from 3 to 15 parts of an organic acid selected fiom the group consisting of oxalic, maleic, fumaric, tartaric, and benzene phosphonic acids, characterized by the property of long storability in a humid atmosphere.

2. The compositions of claim 1 in which the sulfate of the optical bleaching agent is used.

3. The compositions of claim 1 in which the chloride of the optical bleaching agent is used.

4. The compositionsof claim 1 in which the optical bleaching agent is '4-methyl-7-diethylaminocoumarin.

5. The compositions of claim 2 in which the optical bleaching agent is 4-methyl-7-diethylaminocoumarin.

6. The composition of claim 5 in which the organic acid is oxalic acid.

7. The composition of claim 5 inwhich the organic acid is fumaric acid.

8. The composition of claim 5 in which the organic acid is maleic acid.

9. The composition of claim '5 in which the organic acid is tartaric acid.

10. The composition of claim 5 inwhich the organic acid is 'benzenephosphonic acid.

References Cited in the file of this patent UNITED STATES PATENTS 2,654,713 Fleck Oct. 6, 1953 

1. A SOLID OPTICAL BLEACHING COMPOSITION COMPRISING A MIXTURE OF 1 PART, CALCULATED ON THE FREE BASE, OF A STRONG-INORGANIC ACID SALT OF AN OPTICAL BLEACHING AGENT OF THE FORMULA: 